#pragma once

#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <algorithm>
#include <mutex>
#include <cassert>
#include <jsoncpp/json/json.h>

#include "../comm/util.hpp"
#include "../comm/log.hpp"
#include "../comm/httplib.h"
#include "oj_model.hpp"
// #include "oj_model2.hpp"
#include "oj_view.hpp"

namespace ns_control
{
    using namespace std;
    using namespace ns_log;
    using namespace ns_util;
    using namespace ns_model;
    using namespace ns_view;
    using namespace httplib;
    // 提供主机服务
    class Machine
    {
    public:
        std::string ip;  // 编译服务的ip
        int port;        // 编译服务的端口
        uint64_t load;   // 编译服务的负载
        std::mutex *mtx; // mutex禁止拷贝，所以使用指针
    public:
        Machine()
            : ip(""), port(0), load(0), mtx(nullptr)
        {}
        ~Machine()
        {}

    public:
        void IncLoad()
        {
            if (mtx)
                mtx->lock();
            load++;
            if (mtx)
                mtx->unlock();
        }
        void DecLoad()
        {
            if (mtx)
                mtx->lock();
            load--;
            if (mtx)
                mtx->unlock();
        }
        void ResetLoad()
        {
            if (mtx)
                mtx->lock();
            load = 0;
            if (mtx)
                mtx->unlock();
        }
        uint64_t Load()
        {
            uint64_t _load = 0;
            if (mtx)
                mtx->lock();
            _load = load;
            if (mtx)
                mtx->unlock();
            return _load;
        }
    };

    const std::string service_machine = "./conf/service_machine.conf";
    // 负载均衡模块
    class LoadBlance
    {
    private:
        std::vector<Machine> machines; // 所有可用的主机
        std::vector<int> online;       // 所有在线的主机id
        std::vector<int> offline;      // 所有离线的主机id
        std::mutex mtx;                // 保证LoadBlance的数据安全
    public:
        LoadBlance()
        {
            assert(LoadConf(service_machine));
            LOG(INFO) << "加载 " << service_machine << " 成功"
                      << "\n";
        }
        ~LoadBlance() {}
        bool LoadConf(const std::string &machine_conf)
        {
            std::ifstream in(machine_conf);
            if (!in.is_open())
            {
                LOG(FATAL) << "加载：" << machine_conf << "失败"
                           << "\n";
                return false;
            }
            std::string line;
            while (std::getline(in, line))
            {
                std::vector<std::string> tokens;
                StringUtil::SplitString(line, &tokens, ":");
                if (tokens.size() != 2)
                {
                    LOG(WARNING) << "切分" << line << "失败"
                                 << "\n";
                    continue;
                }
                Machine m;
                m.ip = tokens[0];
                m.port = atoi(tokens[1].c_str());
                m.load = 0;
                m.mtx = new std::mutex();
                online.push_back(machines.size());
                machines.push_back(m);
            }
            in.close();
            return true;
        }
        bool SmartChoice(int *id, Machine **m)
        {
            // 1.使用选择好的主机（更新主机的负载）
            // 2.我们需要可能离线该主机
            mtx.lock();
            //轮询+hash
            int online_num = online.size();
            if (online_num == 0)
            {
                mtx.unlock();
                LOG(FATAL) << "所有后端编译主机已经离线，请运维人员修复"
                           << "\n";
                return false;
            }
            // 通过遍历的方式找到所有负载最小的机器
            uint64_t min_load = machines[online[0]].Load();
            *id = online[0];
            *m = &machines[online[0]];
            for (int i = 0; i < online_num; i++)
            {
                uint64_t cur_load = machines[online[i]].Load();
                if (min_load > cur_load)
                {
                    min_load = cur_load;
                    *id = online[i];
                    *m = &machines[online[i]];
                }
            }
            mtx.unlock();
            return true;
        }
        void OfflineMachine(int which)
        {
            mtx.lock();
            for (auto iter = online.begin(); iter != online.end(); iter++)
            {
                if (*iter == which)
                {
                    machines[which].ResetLoad();
                    online.erase(iter);
                    offline.push_back(which);
                    break;
                }
            }
            mtx.unlock();
        }
        void OnlineMachine()
        {
            // 统一上线
            mtx.lock();
            online.insert(online.end(), offline.begin(), offline.end());
            offline.erase(offline.begin(), offline.end());
            mtx.unlock();
            LOG(INFO) << "所有的主机重新上线了"
                      << "\n";
        }

        // for test
        void ShowMachines()
        {
            mtx.lock();
            std::cout << "当前在线主机列表：";
            for (auto &id : online)
            {
                std::cout << id << " ";
            }
            std::cout << std::endl;
            std::cout << "当前离线主机列表：";
            for (auto &id : offline)
            {
                std::cout << id << " ";
            }
            std::cout << std::endl;
            mtx.unlock();
        }
    };

    class Control
    {
    private:
        Model _model;
        View _view;
        LoadBlance _load_blance;

    public:
        Control() {}
        ~Control() {}
        void RecoveryMachine()
        {
            _load_blance.OnlineMachine();
        }
        // 根据题目数据构建网页
        bool AllQuestions(string *html)
        {
            vector<struct Question> all;
            if (_model.GetAllQuestions(&all))
            {
                sort(all.begin(), all.end(), [](const struct Question &q1, const struct Question &q2)
                     { return atoi(q1.number.c_str()) < atoi(q2.number.c_str()); });
                //获取所有题目成功，将所有的题目数据构建成网页
                _view.AllExpandHtml(all, html);
                return true;
            }
            else
            {
                *html = "获取题目失败";
                return false;
            }
        }
        bool Question(const string &number, string *html)
        {
            struct Question q;
            if (_model.GetOneQuestion(number, &q))
            {
                // 获取指定的题目
                _view.OneExpandHtml(q, html);
                return true;
            }
            else
            {
                *html = "指定题目：" + number + " 不存在";
                return false;
            }
        }
        void Judge(const std::string &number, const std::string in_json, std::string *out_json)
        {
            LOG(DEBUG) << in_json << "\nnumber:" << number << "\n";
            // 0.根据题目编号，直接拿到对应的题目细节
            struct Question q;
            _model.GetOneQuestion(number, &q);
            // 1. in_json进行反序列化，得到题目id，得到用户提交的源代码，input
            Json::Reader reader;
            Json::Value in_value;
            reader.parse(in_json, in_value);
            std::string code = in_value["code"].asString();
            // 2. 重新拼接用户代码+测试用例代码，形成新的代码
            Json::Value compile_value;
            compile_value["input"] = in_value["input"].asString();
            compile_value["code"] = code + "\n" + q.tail;
            compile_value["cpu_limit"] = q.cpu_limit;
            compile_value["mem_limit"] = q.mem_limit;
            Json::FastWriter writer;
            std::string compile_string = writer.write(compile_value);
            // 3. 选择负载最低的主机，然后发起http请求，得到结果
            // 规则：一直选择，直到主机全部挂掉
            while (true)
            {
                int id = 0;
                Machine *m = nullptr;
                if (!_load_blance.SmartChoice(&id, &m))
                {
                    break;
                }
                // 4 . 发起请求
                Client cli(m->ip, m->port);
                m->IncLoad();
                LOG(INFO) << "选择主机成功，主机id：" << id << "详情：" << m->ip << " : " << m->port
                          << "当前主机负载：" << m->Load() << "\n";
                if (auto res = cli.Post("/compile_and_run", compile_string, "application/json;charset=utf-8"))
                {
                    // 5. *out_json = 将结果赋值给 out_json
                    if (res->status == 200)
                    {
                        *out_json = res->body;
                        m->DecLoad();
                        LOG(INFO) << "请求编译和运行服务成功。。"
                                  << "\n";
                        break;
                    }
                    m->DecLoad();
                }
                else
                {
                    // 请求失败
                    LOG(ERROR) << "当前主机id："
                               << "详情：" << id << m->ip << " : " << m->port << "可能已经离线"
                               << "\n";
                    _load_blance.OfflineMachine(id);
                    _load_blance.ShowMachines(); // debug
                }
            }
        }
    };
} // namespace ns_control
